Winding tension control system

ABSTRACT

Winding apparatus for taking up a sheet into a roll state by the center drive has the winding tension controlled in such way that a winding radius is detected, that the detected signal is subjected to a calculation for comparison with a tension value under a tension gradient previously set, and that a signal of the calculated tension value is amplified. For the tension control, a theoretical equation is adopted in which the winding radius is a variable and in which certain conditions are taken into consideration. The winding tension control is accomplished by means of a torque actuator which is coupled with a winding shaft. In an arithmetic circuit, the detected winding radius is processed in an analog or digital system, and the comparison is made between the theoretical tension value evaluated and the appropriate tension value previously set. The tension control system is also applied to winding apparatus which jointly uses the center drive system and the surface friction drive system.

United States Patent 91 Kataoka Mar. 18, 1975 WINDING TENSION CONTROL SYSTEM Primary E.raminerEdward J. McCarthy [75] Inventor: Himshi Kataoka, WmMishima Attorney, Agent, or Firm-Stevens, Davis, Miller &

Japan Mosher [73] Assignee: Kataolta Machine Product Co., Ltd., [57] ABSTRACT lyo'M'shlma'shli Japan Winding apparatus for taking up a sheet into a roll [22] Filed: July 16, 1973 state by the center drive has the winding tension controlled in such way that a winding radius is detected, Appl' 379836 that the detected signal is subjected to a calculation for comparison with a tension value under a tension [30] Foreign Application P i rit D t gradient previously set, and that a signal of the calcu- July 17, 1972 Japan 4771419 iaed ieiisim value is amplified For iensim trol, a theoretical equation is adopted in which the 521 U.S. Cl. 242175.51 it radius is variable which 5 1 Int. Cl B65h 25/04 diimns are take" ciisideiaiim The winding 531 Field of Search 242/7551 75.5 75.52 conimi is accomplished by means of H 245/7553 tuator which is coupled with a winding shaft. In an arithmetic circuit, the detected winding radius is pro- [56] Rflerences Cited cessed in an analog or digital system, and the comparison is made between the theoretical tension value UNITED STATES PATENTS evaluated and the appropriate tension value previously 7/1944 Larsen 242/755i set. The tension control system is also applied to windg g ti 7 ing apparatus which jointly uses the center drive sys- 3223906 lzllgs 'f jiii 242/75'51 x tem and the surface friction drive system. 2 Claims, 13 Drawing Figures e ision roaoue INDlCATION INDICATION I0 II F 1; Designer) i i f TEN ton TORQUE VALUE F0 2225:: zg szzgfgs ma ACTUATOR DESIRED fl- (A) 12:22? VALUE f PATENTEU MRI 8 W5 TENSION F sum 5 or 9 Fl 6. 6A

6.2 (is T :10 R

RADIUS OF WINDING ROLL RADIUS '1'- R H'ATENTEU MW 8 W5 SHEET 8 BF 9 FIG.6C

RADIUS R PM'ENTED 1 W75 3.87 l .598

sum? nr 9 1 WINDING TENSION CONTROL SYSTEM The present invention relates to a tension control system for winding apparatus. More particularly, it relates to a winding tension control system for apparatus which takes up a sheet or the like by employing the center drive system or both the center drive and the surface friction drive.

In case of winding a sheet of paper, plastic film, cloth or the like on a take-up core by the center drive system and thus manufacturing a roll product, a method having been generally adopted consists in that, for the winding operation, a differential mechanism composed of, for example, a hydraulic circuit or a gearing is provided for the driving relation between a touch roll and a winding roll.

in this case, on the basis of the principle of such differential mechanism, an insufficient winding torque is generated on account of an inversely proportional decrease in a supply torque as is attendant upon an increase in the winding radius, namely, an increase in the winding load. This is quite irrational in practical use. Therefore, braking means is coupled to the touch roll, and the supply torque on the touch roll side is regulated on occasion. In this way, the winding operation can be laboriously carried out.

Accordingly, a tension value acting on the sheet hand during the winding operation is not, in itself, a factor which is directly handled. This leads to the radical disadvantage of the prior art that human works relying on the senses of sight and touch of an operator, such as seeing the state of the winding roll or the moving sheet ban and touching the roll or the sheet by hand, are required.

As a comparatively precise method, there has been known one wherein a device in which control signals and output torques are in direct proportion or approximately in direct proportion is coupled to an actuator for supplying the winding torque, a signal of the increase of the winding radius is directly derived as a command signal for the actuator, and the range of the signal is mechanically designed beforehand, whereby the winding operation is performed under a theoretically fixed tension or at a previously set tension gradicm. In this case, the setting of tension values can be readily regulated by an adjuster, such as variable resistor, provided on an external control board or the like. However, the tension gradient or tapering tension between the initial winding and the final winding, being the most important in the winding operation of this type, cannot be varied by any other method than changing the mechanical coupling at the winding radius-detecting part. Besides, the radius detecting signal is directly employed as the command signal for the torque control of the actuator, so that the tension value acting on the sheet band during the winding process is not, in itself, a factor to-be-handled to the disadvantage.

As stated above, the prior art is disadvantageous in the working property and the controllability. Moreover, in case of applying it to, for example, a slitter rewinder, means associated with the actuator and the means to detect the radius and to generate the command signal, such as the variable resistor which is comparatively large in size and in capacity, need be attached to winding arm section. This leads to further disadvantages that the structure of the section becomes large, and that the working property for maintenance, inspection etc. is degraded.

Since, on the other hand. the winding arm need be as light as possible for the purpose of sensitively adjusting the touch pressure of the winding roll, the foregoing method is difficult to be generally applied.

An object of the present invention is to provide a system in which a tension is gradually decreased on the basis of a predetermined relational equation with increases in the winding roll radius, so as to produce a winding roll having a good winding figure owing to uniform stiffness of inner and outer winding layers or to appropriately controlled winding tightness for every laminated layer.

Another object of the present invention is to provide a system which can automatically control the winding torque as it is detecting the radius of the winding roll.

Still another object of the present invention is to provide a system which allows a sheet to be wound by maintaining the tension at an appropriate value even in case where the tension just before the winding roll cannot be directly detected.

Yet another object of the present invention is to provide a system which allows a sheet to be wound by appropriately controlling the tension even in case where it cannot be handled as a precise tension value by the surface friction drive.

The present invention consists in that, as only a signal of the radius ofa winding roll under the winding operation is being detected, a winding tension value is evaluated from the detected value by means of an arithmetic circuit, and that as a winding torque is being automatically controlled by a control signal produced by the comparison between the evaluated value and an appropriate tension value previously given as a set value, the winding operation is carried out.

in accordance with the present invention, the tension is electronically controlled in the two factors of a tension value and a tension gradient, and besides, it is possible to directly indicate the tension and a torque and to carry out the tension control as a simple dial setting operation, so that the working property is very good and that the tension management during running is standardized and becomes extremely accurate and easy.

In case of slitting out a number of narrower sheets of different slit widths from a supplied sheet band of large width and taking up the narrower sheets into individual winding rolls, the automatic control can be made under the state under which setting elements for the individual winding rolls are respectively and independently regulated to desired appropriate values, so that the adjustments of the tensions in the case of such operation can be readily made.

The present invention resides in the method in which an electric signal is derived from a mechanical part, the signal is subjected to a logical control by a control device externally provided, and the resultant command signal is again fed into the mechanically operating part, so that the mechanical part can be made compact and simple and that the maintenance and inspection of the mechanical part can be facilitated.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a basic control flow chart of the system of the present invention;

FIG. 2 is a block diagram of a concrete embodiment in the case where the control system is applied to an analog control system;

FIG. 3 is a control flow chart showing a concrete embodiment in the case where a hybrid digital and analog control system is applied;

FIG. 4 is a diagram showing a winding tension winding radius characteristic;

FIG. 5 is a diagram showing winding torque winding radius characteristics;

FIGS. 6A, 6B and 6C are diagrams of tension winding radius characteristics with the tension gradient taken as a parameter;

FIG. 7 is a side view of winding apparatus to which the system of the present invention is applied;

FIGS. 8 and 9 are a side view and a plan view, respectively, showing winding apparatus which is driven for winding by means of a common shaft;

FIG. 10 is an enlarged sectional view taken along lines XX in FIG. 8; and

FIG. 11 is a side view of winding apparatus of the sectional drive system.

FIG. 1 is a basic control flow chart of the winding tension control system of the present invention, FIG. 2 is a block diagram of a case where the invention is applied to an analog control system, and FIG. 3 is a control flow chart of a case where a hybrid digital and ana log control system is employed.

In FIG. 1, a desired tension value F and a desired tension gradient 3 are given to a setting unit 10. The tension value is compared with a winding radiusdetecting signal by a comparison control unit 11, which provides a torque setting signal as its output. The output signal is fed via an amplifier unit 12 and a torque actuator 13 to a winding axis 14, to control the torque of the winding axis 14. A winding radius at the winding axis 14 is detected by a detecting unit 15, and is fed back to the comparison control unit 11. The signal derived from the comparison unit 11 indicates a tension value F at any winding radius R. while a signal derived from the amplifier unit 12 denotes a winding torque T under the same condition.

The present invention controls the torque for winding in such way that the detecting signal for the winding roll radius is subjected to a calculation according to a theoretical equation, and that the tension value thus obtained is compared with the previously set tension value. As the theoretical equation, the following is adopted:

where R radius of the winding roll (mm),

R radius of the initial winding (mm),

R radius of the final winding or maximum radius of the winding roll (mm),

F tension value at the initial winding (kg/cm),

B (F I'D/F (here, F, denotes a tension value at the maximum winding radius), that is, the coefficient of the tension gradient (tapering tension) between the initial winding and the final winding, and

0 any positive rational number such as /2, l and 2.

The characteristic curve between the winding radius and the tension to be controlled on the basis of the theoretical equation is as shown in FIG. 4, and gradually decreases the tension from the value F to the value F over the range of from the initial winding radius R to the final winding radius R,,,,,

A block diagram of an analog arithmetic circuit for calculating the winding tension F from the signal of any winding radius R by the use of the above theoretical equation, is as shown in FIG. 2. In case where an arithmetic part and comparison control part are digitized. a circuit for the calculation is as depicted by the flow chart in FIG. 3. In these circuits, the signal delivered from the final stage is the torque command signal F X R T.

In the analog arithmetic circuit illustrated in FIG. 2, a signal derived from a part A represents the tension value (F) at any winding radius R, while a signal derived from a part B denotes the winding torque (T) under the same condition. It has been experimentally verified that the tension value (F) and the winding torque (T) are given as characteristic curves versus the radius R in FIG. 6A and in FIG. 5, respectively.

The characteristic curves in FIG. 6A correspond to a case where 6= l in the theoretical equation. the coefficient B is made a parameter and the winding radius R is made a variable, and where the winding tension F is so controlled as to gradually decrease linearly. Characteristics in FIG. 6B are adopted in case of aiming at curved variations at 6= V2, while characteristics in FIG. 6C are adopted in case of aiming at curved variations at 6 2. In the digital and analog control, a multiple type control is of course possible.

FIG. 7 shows a side of winding apparatus to which the system of the present invention is applied. The apparatus uses the center drive and the friction drive jointly. A fixed bracket 18 is provided with a shaft 20 for supporting one end ofa swivel arm 19. Means 21 to detect the swivel angle of the arm 19 is mounted by the side of the shaft 20. At the back of the arm 19, a pneumatic cylinder mechanism 22 for cushioning is disposed between the arm 19 and the bracket 18. A winding shaft 23 is provided at the front end of the arm, while a torque actuator 24 is provided at substantially the central part of the arm. Transmission means 25 is extended over between the taking-up shaft 23 and the torque actuator 24, another transmission means 26 between the torque actuator 24 and the shaft 20, and further transmission means 27, such as chain, between the shaft 20 and the detector 21.

Illustrated in FIG. 7 is a course in which a sheet 30 is being wound on a bobbin 29, attached to the takingup shaft 23, into the state of a roll 31 by means of a touch roller 28. The sheet 30 is wound up into the roll state by the actions of the friction drive owing to the touch roller 28 and the shaft driving torque exerted on the taking-up shaft 23 under the torque control owing to the torque actuator 24. The arm 19 swivels about the fulcrum shaft 20 while, following the increase of the radius of the winding roll, it holds the contact pressure between the touch roller 28 and the winding roll 31 in an appropriate and constant slight pressure state by means of the pneumatic cylinder mechanism 22 (which may also be a hydraulic device or the like).

Accordingly, the touch roller 28 constitutes an important element which smoothly guides the sheet 30 to a position just before the winding roll 31 as it is removing introduction of air.

The fulcrum shaft 20 is a driving shaft. and transmits a driving force through the transmission means 26 onto the input side of the actuator 24. The increase of the winding radius can be substituted by an angular displacement of the swivel arm 19. A signal of a detection value corresponding to the quantity of increase of the winding radius can therefore be provided in such manner that the swivel arm 19 is interlocked with the electric signal converter or detector 21, such as a highly precise potentiometer for deriving very small signals, by the transmission means 27 which is comparatively fine and which has an accurate transmission ratio.

In case of sequence-controlling the actuator by the torque setting signal, the actuator need have such characteristic that control signals and output torques are in direct proportion or approximately in direct proportion. For example. a DC motor or an electromagnetic powder clutch is employed. Besides the employment of the clutch of this type, a torque motor or a DC motor (not shown) may be directly controlled.

As previously stated, FIG. 1 is the diagram of the control system based on the detected value of the winding radius. In accordance with the control system, using only the winding radius signal R of the detected value of the winding roll radius, the difference between the winding tension value calculated from the theoretical equation and the appropriate tension value given to the setting unit beforehand and stored in the comparison control unit is produced as a command signal. The command signal is amplified by the action of the amplitier unit into an electric power signal necessary to operate the actuator 24. The torque control of the actuator 24 is made by the electric power signal, to drive the winding shaft 23.

FIGS. 8 to show a slitter winder in which the winding torque is detected by a common shaft.

FIG. 8 is a side view, while FIG. 9 is a plan view. A sheet band 30 supplied from a winding-out portion is fed via a guide roll 43 to an expander roll 44, and has its wrinkles smoothed by the expanding action of the expander roll 44. It is further fed via a delivery roll 45 to a slotted slit drum 46 and a leather cutter 47, and is continuously slitted into predetermined narrower sheets 41, 42 etc. by the slitting action of the constituent elements 46 and 47. The slitted sheets are wound up into winding rolls 51, 52, 53, 54 held in contact with touch rolls 48, 49. The winding rolls 51, 52, 53, 54 are taken up on winding shafts 59, 61, 61, 62 provided crosswise at the front ends of swivel arms 57a, 57b and 58a, 581: which operate so as to turn about fulcrum shafts 55, 56 and following increases in the winding radii. That is, in case of the present embodiment, the winding roll 51 is supported on the winding shaft 59 by the arms 57a, 57b on both sides. The other winding rolls are similarly supported. In case where the narrower sheet of the winding roll is of a comparatively small width, the working property at roll exchange can be enhanced by employing a structure in which, as is the case of the winding roll 52, the winding shaft 61 is supported by only a one-side arm 60.

The touch rolls 48, 49 and the respective winding rolls 51 etc. can be normally held at suitable contact pressures by adjusting the operating forces of regulating devices. such as air cylinders, 62 which are independently equipped for the respective swivel arms 570 etc. The associated construction between the swivel arms 570 etc. and the winding shafts 59 etc. is as shown by way of example in FIG. 10.

Referring to FIG. 10, the winding shaft 59 for taking up the winding roll 51 has its both ends supported by the swivel arms 57a and 57b. On the side of the arm 57a, there are provided means related to the torque control and means related to the radius detection. The fulcrum shaft 55 of the swivel arms 57a, 57b serves also as a driving shaft for supplying the winding torque. An intermediate transmission ring 64 is rotated by a slide key structure 63. Over an end of the ring 64, there is extended transmission means 66 which transmits the torque onto the input side of an actuator 65. Further. the swivel arm 570 which can freely turn through hearings 67, 67 at the outer periphery of the intermediate transmission ring 64 is carried on a fixed supporting base 68. The swivel arm 57a can follow increases in the winding radius. The quantity of torque controlled by the actuator 65 is supplied to the winding shaft 59 via transmission means, such as belt. 69. The winding radius-detecting part has such construction that the angular displacement of the swivel arm 57a is coupled through coupling means, such as chain being relatively fine and having a highly accurate transmission ratio. 70 to an electric signal converter, such as potentiometer, 71. On the other hand, the side of the swivel arm 57h has a construction similar to that of the side of the swivel arm 57a and supports the other end of the winding shaft 59 so as to freely rotate the shaft, but it includes neither the means related to the torque control nor the means related to the radius detection. In case of the drive,'a fixed torque is first transmitted from the fulcrum shaft 55, being the driving shaft, to the intermediate transmission ring 64, and is continually supplied via the transmission means 66 onto the input side of the actuator 65. Subsequently, a signal of the winding radius is detected by the electric signal converter 71, the foregoing tension comparison control based on the signal is performed to derive a signal for controlling the actuator, and the actuator is controlled. Then, an appropri ate driving torque is generated on the output side of the actuator, and is delivered to the winding shaft 59 by the transmission means 69. As a result, the winding roll 51 takes up the narrower sheet 41 under the appropriate winding driving torque, namely, under an appropriate winding tension.

In FIG. 9, reference numerals 73 and 74 designate arms which support a shaft 75 of the roll 54 for winding the sheet in a larger width.

As described above, the tension is electronically controlled in the two factors of the tension value and the tension gradient.

Besides, it is possible to directly indicate the tension and the torque, and to carry out the tension control as a simple dial setting operation. Therefore, the working property is very good, and the tension management during running is standardized and becomes extremely accurate and easy.

FIG. 11 is a side view illustrating a case where the present invention is applied to a slitter winder of the sectional drive system. As shown in the figure, a fixed bracket 78 has a shaft 80 for supporting one end of a swivel arm 79. By the side of the shaft 80, there is mounted a device 81 for detecting the swivel angle of the arm 79. A pneumatic cylinder mechanism for cushioning 82 is provided between the arm 79 and the bracket 78 at the back of the arm 79, while a winding shaft 83 is provided at the front end of the arm 79. In front of the bracket 79, an actuator 84 is disposed. A gearing 86 is provided between the winding shaft 83 and an intermediate shaft 85, while transmission means 87 is extended over between the intermediate shaft 85 and the shaft 80. Another transmission means 89 is extended over between a shaft 88 of the actuator 84 and the shaft 80, the third transmission means 92 between the shaft 88 of the actuator 84 and a shaft 91 of a motor 90, and further, a transmission member, such as chain, 93 between the shaft 80 and the detector 81.

illustrated in FIG. I] is the aspect in which, after slitting a sheet 30, each slit sheet is wound up on the winding shaft 83 in the state of a roll 94 by a touch roller 95. The assemblies of the winding apparatus are arranged, as shown, symmetrically with the touch roll 95 held therebetween. Full lines of the left assembly indicate the position of initial winding, while chain lines represent the position of final winding. The sheet 30 continu ously fed passes through a guide roll 96. As it is removing its wrinkles by the expanding action of an expander roll 97, it is cut into wide sheets of a predetermined width on a slit drum 98 by the action of a leather cutter 99. The cut sheets are brought into contact with the touch roll 95 via a delivery roll 100, and are respec tively distributed to and taken up by bobbins of the winding shafts contacted with the front and rear of the touch roll.

The expander roll 97, the slit drum 98, the delivery roll 100 and the touch roll 95 are interlocked. and are respectively driven by a varying speed motor (not shown).

Each winding shaft 83 is driven in the sectional drive system via the motor 90 and the transmission means 92, 89, 87, 86.

Since the sheet 30 fed out by the rolls posterior to the expander roll 97 is guided in the shape of the letter S, frictional forces owing to film lap angles are produced. Thus, a non-uniform state of supply on the side of the guide roll 96 is regulated by the group of the rolls, to make smooth the winding operation of the center drive as employs the tension control.

In order to normally exert an appropriate and constant slight pressure between the touch roll 95 and each winding roll 94, the pneumatic (or hydraulic) cylinder mechanism 82 is provided. As a result, the influence of the surface drive due to the contact between the touch roll 95 and the roll 94 is released, to make the center drive of the winding shaft 83 more effective.

The detection of the winding radius is carried out in such a way that an angular displacement of the swivel arm 79 due to a swivel is transmitted to the electric signal converter, such as potentiometer, 81 by the transmission means 93. A signal obtained in the converter 81 is fed back to the comparison control unit 11 of the circuit as shown in FIG. 1. A control signal produced by the unit 11 is applied to the torque actuator 84 in FIG. 11.

in performing the present invention, it is necessary to consider the compensation of mechanical loss and inertia which are determined by conditions in the design of the apparatus. Conventional correcting means can, of course, be adopted in dependence on such conditions.

What we claim is:

l. A winding tension control system comprising:

a. a winding shaft for taking up a sheet into a roll state,

b. detecting means for continually detecting the radius of a winding roll under a winding operation,

c. an arithmetic circuit which calculates a tensile value at an arbitrary radius of said winding roll on the basis of a theoretical equation,

d. a comparison control unit which multiplies a winding radius-detecting signal obtained by said detecting means, by said tensile value calculated by said arithmetic circuit and which thus outputs a desired winding torque signal, and

e. a torque actuator which controls a winding torque of said winding shaft by the output signal from said comparison control unit.

2. The winding tension control system as defined in claim 1, characterized in that said theoretical equation is given by:

for the calculation of said tensile value where R radius of said winding roll,

R radius of an initial winding,

R Maximum radius of said winding roll,

F tension value at the initial winding,

B coefficient of a tapering tension as is expressed by (F,, F )F where F, denotes a tension at the maxi mum winding radius, and

6 any positive rational number such as k, l and 2. 

1. A winding tension control system comprising: a. a winding shaft for taking up a sheet into a roll state, b. detecting means for continually detecting the radius of a winding roll under a winding operation, c. an arithmetic circuit which calculates a tensile value at an arbitrary radius of said winding roll on the basis of a theoretical equation, d. a comparison control unit which multiplies a winding radiusdetecting signal obtained by said detecting means, by said tensile value calculated by said arithmetic circuit and which thus outputs a desired winding torque signal, and e. a torque actuator which controls a winding torque of said winding shaft by the output signal from said comparison control unit.
 2. The winding tension control system as defined in claim 1, characterized in that said theoretical equation is given by: F F0 (1 - Beta (R - Rmin/Rmax - Rmin) ) for the calculation of said tensile value where R : radius of said winding roll, Rmin : radius of an initial winding, Rmax : Maximum radius of said winding roll, F0 : tension value at the initial winding, Beta : coefficient of a tapering tension as is expressed by (F0 - F1)F0 where F1 denotes a tension at the maximum winding radius, and theta : any positive rational number such as 1/2 , 1 and
 2. 